<?php

/**
 * AF Translate Core AI Engine Subsystem Layer
 *
 * Consolidated execution layer handling both cloud-based LLM architectures 
 * and Traditional Neural Machine Translation (NMT) platforms.
 *
 * @package    AF_Translate
 * @subpackage AF_Translate/includes
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

class AF_Translate_AI_Engine 
{
    /**
     * Cleans conversational filler, markdown layout markup, and localized phrases from AI responses.
     * Engineered with comprehensive filter vectors to remain fully extendable.
     *
     * @param string $text Raw text payload response from the AI node.
     * @return string Fully sanitized, raw translation output string.
     */
    public static function clean_model_response( $text ) {
        $original_text =$text;
        $text          = trim($text );

        // Multilingual pattern matrix targeting common conversational introduction styles
        $patterns_to_remove = array(
            // English Vectors
            '/^the translation for.*is:\s*/i',
            '/^here is the translation.*:\s*/i',
            '/^translation:\s*/i',
            '/^translated text:\s*/i',
            
            // German Vectors (Fixes conversational context responses)
            '/^die übersetzung für.*lautet:\s*/ui',
            '/^hier ist die übersetzung.*:\s*/ui',
            '/^übersetzung:\s*/ui',
            
            // Spanish Vectors
            '/^la traducción de.*es:\s*/ui',
            '/^traducción:\s*/ui',
            
            // French Vectors
            '/^la traduction de.*est:\s*/ui',
            '/^traduction:\s*/ui'
        );

        /**
         * Filter the regex patterns applied to strip out introductory conversational text.
         * Use this hook to register custom structural phrases or expressions.
         *
         * @param array $patterns_to_remove Array of regex pattern strings.
         */
        $patterns_to_remove = apply_filters( 'af_translate_model_response_cleanup_patterns',$patterns_to_remove );

        if ( is_array( $patterns_to_remove ) && ! empty( $patterns_to_remove ) ) {$text = preg_replace( $patterns_to_remove, '',$text );
        }

        // Post-regex cleanup to strip trailing/leading markdown bold formatting and raw quotation blocks
        $text = trim($text );
        $text = trim($text, '*"' );
        $text = trim($text );

        /**
         * Filter the finalized cleaned translation string before it returns to the layout pipeline.
         *
         * @param string $text          The sanitized translation text.
         * @param string $original_text The exact raw response text returned by the API.
         */
        return apply_filters( 'af_translate_cleaned_model_response', $text,$original_text );
    }

    /**
     * Route and Process a Single Workbench String Translation
     */
    public static function translate_single( $source_text, $target_locale,$provider = '' ) {
        $settings = get_option( 'af_translate_api_settings', array() );$provider = self::resolve_active_provider( $settings,$provider );

        if ( self::is_sandbox_mode( $settings,$provider ) ) {
            return self::simulate_single_sandbox( $source_text,$target_locale );
        }

        switch ( $provider ) {
            case 'gemini':    return self::call_gemini( $source_text, $target_locale,$settings );
            case 'openai':    return self::call_openai_single( $source_text, $target_locale,$settings );
            case 'anthropic': return self::call_anthropic( $source_text, $target_locale,$settings );
            case 'grok':      return self::call_grok( $source_text, $target_locale,$settings );
            case 'deepl':     return self::call_deepl( $source_text, $target_locale,$settings );
            case 'google':    return self::call_google( $source_text, $target_locale,$settings );
            case 'microsoft': return self::call_microsoft( $source_text, $target_locale,$settings );
            case 'lecto':     return self::call_lecto( $source_text, $target_locale,$settings );
            default:
                return new WP_Error( 'unmapped_provider', __( 'Selected single routing engine lacks an active payload class handler.', 'af-translate' ) );
        }
    }

    /**
     * Process Batch Catalog Array Configurations systematically
     */
    public static function translate_batch( $strings_array, $target_locale,$provider = '' ) {
        $settings = get_option( 'af_translate_api_settings', array() );$provider = self::resolve_active_provider( $settings,$provider );

        if ( self::is_sandbox_mode( $settings,$provider ) ) {
            return self::simulate_batch_sandbox( $strings_array,$target_locale );
        }

        switch ( $provider ) {
            case 'gemini':
                return self::call_gemini_batch( $strings_array, $target_locale,$settings );
            case 'openai':
                return self::call_openai_batch( $strings_array, $target_locale,$settings );
            case 'anthropic':
            case 'grok':
            case 'deepl':
            case 'google':
            case 'microsoft':
            case 'lecto':
                $translated_matrix = array();
                foreach ( $strings_array as $index =>$text ) {
                    $translated = self::translate_single($text, $target_locale,$provider );
                    if ( is_wp_error( $translated ) ) {
                        return $translated;
                    }
                    $translated_matrix[ $index ] =$translated;
                }
                return $translated_matrix;
            default:
                return new WP_Error( 'unmapped_provider', __( 'Selected batch routing engine lacks an active payload class handler.', 'af-translate' ) );
        }
    }

    /**
     * ------------------------------------------------------------------
     * COMMON CORE UTILITIES & HELPERS
     * ------------------------------------------------------------------
     */

    /**
     * Execute remote HTTP POST requests with standardized error handling and JSON decoding.
     */
    private static function execute_api_post( $endpoint, $headers,$body, $timeout = 25,$json_encode = true ) {
        $response = wp_remote_post($endpoint, array(
            'timeout' => $timeout,
            'headers' => $headers,
            'body'    => $json_encode ? wp_json_encode( $body ) :$body,
        ));

        if ( is_wp_error( $response ) ) {
            return $response;
        }

        $code    = wp_remote_retrieve_response_code($response );
        $decoded = json_decode( wp_remote_retrieve_body($response ), true );

        if ( $code < 200 || $code >= 300 ) {$msg = __( 'Remote API endpoint communication disruption.', 'af-translate' );
            if ( isset( $decoded['error']['message'] ) ) {
                $msg =$decoded['error']['message'];
            } elseif ( isset( $decoded['message'] ) ) {
                $msg =$decoded['message'];
            }
            return new WP_Error( 'remote_api_error', $msg );
        }

        return $decoded;
    }

    /**
     * Centralized prompt builder to handle string replacements and filters.
     */
    private static function build_llm_prompt( $text, $target_locale,$settings, $provider,$append_instruction = '') {
        if ( 'openai' === $provider ) {$prompt = self::get_openai_system_prompt( $target_locale,$settings );
        } else {
            $prompt_key     = $provider . '_custom_prompt';$default_prompt = 'Translate this WordPress string to {target_language}. Keep code/HTML placeholders identical. CRITICAL: Return ONLY the absolute raw translation text. Do NOT include any conversational text, introductory remarks, explanations, or Markdown formatting.';
            $prompt         = ! empty( $settings[ $prompt_key ] ) ?$settings[ $prompt_key ] :$default_prompt;
            $prompt         = str_replace( '{target_language}', $target_locale,$prompt );
        }

        if ( ! empty( $append_instruction ) ) {
            $prompt .= ' ' .$append_instruction;
        }

        return apply_filters( 'af_translate_llm_system_prompt', $prompt, $text,$target_locale );
    }

    /**
     * Safely extract the active API key.
     */
    private static function get_api_key( $settings,$provider ) {
        if ( 'openai' === $provider ) {
            return ! empty( $settings['openai_key'] ) ? trim( $settings['openai_key'] ) : get_option( 'af_translate_api_key', '' );
        }
        $key_field =$provider . '_key';
        return isset( $settings[$key_field ] ) ? trim( $settings[$key_field ] ) : '';
    }

    private static function call_gemini( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'gemini' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Gemini API key is empty.', 'af-translate' ) );
        }

        $model    = ! empty( $settings['gemini_model'] ) ? trim( $settings['gemini_model'] ) : 'gemini-3.1-flash-lite';
        $prompt   = self::build_llm_prompt( $text, $target_locale, $settings, 'gemini' );
        $endpoint = 'https://generativelanguage.googleapis.com/v1beta/models/' . sanitize_text_field( $model ) . ':generateContent?key=' . $api_key;

        $payload = apply_filters( 'af_translate_llm_request_body', array(
            'contents'          => array( array( 'parts' => array( array( 'text' => $text ) ) ) ),
            'systemInstruction' => array( 'parts' => array( array( 'text' => $prompt ) ) ), // Fixed: Removed extra outer array layout
            'generationConfig'  => array( 'temperature' => isset( $settings['pro_temperature'] ) ? (float) $settings['pro_temperature'] : 0.1 )
        ), 'gemini' );

        $body = self::execute_api_post( $endpoint, array( 'Content-Type' => 'application/json' ), $payload, 25 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['candidates'][0]['content']['parts'][0]['text'] ) ) {
            return self::clean_model_response( $body['candidates'][0]['content']['parts'][0]['text'] );
        }
        return new WP_Error( 'api_error', __( 'Gemini execution loop failed.', 'af-translate' ) );
    }

    private static function call_gemini_batch( $strings_array, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'gemini' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Gemini API key is empty.', 'af-translate' ) );
        }

        $model    = ! empty( $settings['gemini_model'] ) ? trim( $settings['gemini_model'] ) : 'gemini-3.1-flash-lite';
        $append   = 'CRITICAL REQUIREMENT: Input will arrive as an explicitly indexed JSON object array layout matrix. You must return absolute translation output ONLY as a matching structural JSON object using the identical key assignments. Do not include markdown code wrapping blocks.';
        $prompt   = self::build_llm_prompt( implode( ' ', $strings_array ), $target_locale, $settings, 'gemini', $append );
        $endpoint = 'https://generativelanguage.googleapis.com/v1beta/models/' . sanitize_text_field( $model ) . ':generateContent?key=' . $api_key;

        $payload = apply_filters( 'af_translate_llm_request_body', array(
            'contents'          => array( array( 'parts' => array( array( 'text' => wp_json_encode( $strings_array ) ) ) ) ),
            'systemInstruction' => array( 'parts' => array( array( 'text' => $prompt ) ) ), // Fixed: Removed extra outer array layout
            'generationConfig'  => array(
                'temperature'      => isset( $settings['pro_temperature'] ) ? (float) $settings['pro_temperature'] : 0.1,
                'responseMimeType' => 'application/json'
            )
        ), 'gemini' );

        $body = self::execute_api_post( $endpoint, array( 'Content-Type' => 'application/json' ), $payload, 45 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['candidates'][0]['content']['parts'][0]['text'] ) ) {
            $json_str = trim( $body['candidates'][0]['content']['parts'][0]['text'] );
            $json_str = preg_replace( '/^```json\s*/i', '', $json_str );$json_str = preg_replace( '/\s*```$/', '', $json_str );
            $decoded  = json_decode( trim( $json_str ), true );
            
            if ( is_array( $decoded ) ) {
                return $decoded;
            }
        }
        return new WP_Error( 'gemini_batch_alignment_failed', __( 'Could not securely synchronize translated Gemini dataset matrix structural syntax layout.', 'af-translate' ) );
    }

    private static function call_openai_single( $source_text, $target_locale,$settings ) {
        $api_key = self::get_api_key($settings, 'openai' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'OpenAI API key is empty.', 'af-translate' ) );
        }

        $model    = ! empty( $settings['openai_model'] ) ? $settings['openai_model'] : get_option( 'af_translate_ai_model', 'gpt-4o-mini' );$prompt   = self::build_llm_prompt( $source_text,$target_locale, $settings, 'openai' );$endpoint = ! empty( $settings['openai_custom_endpoint'] ) ? esc_url_raw( $settings['openai_custom_endpoint'] ) : 'https://api.openai.com/v1/chat/completions';

        $payload = apply_filters( 'af_translate_llm_request_body', array(
            'model'       => $model,
            'temperature' => isset( $settings['pro_temperature'] ) ? (float)$settings['pro_temperature'] : 0.2,
            'messages'    => array(
                array( 'role' => 'system', 'content' => $prompt ),
                array( 'role' => 'user', 'content' => $source_text )
            )
        ), 'openai' );

        $headers = array( 'Authorization' => 'Bearer ' .$api_key, 'Content-Type' => 'application/json' );
        $body    = self::execute_api_post($endpoint, $headers,$payload, 45 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['choices'][0]['message']['content'] ) ) {
            return self::clean_model_response( $body['choices'][0]['message']['content'] );
        }
        return new WP_Error( 'api_malformed_response', __( 'OpenAI core node returned an unreadable response layout.', 'af-translate' ) );
    }

    private static function call_openai_batch( $strings_array, $target_locale,$settings ) {
        $api_key = self::get_api_key($settings, 'openai' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'OpenAI API key is empty.', 'af-translate' ) );
        }

        $model    = ! empty( $settings['openai_model'] ) ? $settings['openai_model'] : get_option( 'af_translate_ai_model', 'gpt-4o-mini' );$append   = 'Crucial Instruction: Input will arrive as a serialized JSON object map. You must respond ONLY with a valid JSON object matching the exact key definitions. Do not include markdown wraps or ```json indicators.';
        $prompt   = self::build_llm_prompt( implode( ' ', $strings_array ), $target_locale, $settings, 'openai', $append );
        $endpoint = ! empty( $settings['openai_custom_endpoint'] ) ? esc_url_raw( $settings['openai_custom_endpoint'] ) : '[https://api.openai.com/v1/chat/completions](https://api.openai.com/v1/chat/completions)';

        $payload = apply_filters( 'af_translate_llm_request_body', array(
            'model'           => $model,
            'temperature'     => isset( $settings['pro_temperature'] ) ? (float) $settings['pro_temperature'] : 0.2,
            'response_format' => array( 'type' => 'json_object' ),
            'messages'        => array(
                array( 'role' => 'system', 'content' => $prompt ),
                array( 'role' => 'user', 'content' => wp_json_encode( $strings_array ) )
            )
        ), 'openai' );

        $headers = array( 'Authorization' => 'Bearer ' . $api_key, 'Content-Type' => 'application/json' );
        $body    = self::execute_api_post( $endpoint, $headers, $payload, 45 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['choices'][0]['message']['content'] ) ) {
            $decoded = json_decode( $body['choices'][0]['message']['content'], true );
            if ( is_array( $decoded ) ) {
                return $decoded;
            }
        }
        return new WP_Error( 'batch_alignment_failed', __( 'Could not securely synchronize translated OpenAI dataset matrix trees.', 'af-translate' ) );
    }

    private static function get_openai_system_prompt( $target_locale, $settings ) {
        if ( ! empty( $settings['openai_custom_prompt'] ) ) {
            return str_replace( '{target_language}', $target_locale, $settings['openai_custom_prompt'] );
        }
        return "You are a professional localization engine processing complex core WordPress gettext catalogs. " .
               "Translate the provided text content accurately into the target language code context: '{$target_locale}'. " .
               "CRITICAL: You must preserve all raw formatting parameters, HTML entities, and structural printf string layout placeholders exactly as they appear in the source string. " .
               "CRITICAL: Return ONLY the absolute raw translation text. Do NOT include any conversational text, introductory remarks, explanations, or Markdown formatting.";
    }

    private static function call_anthropic( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'anthropic' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Anthropic API key is empty.', 'af-translate' ) );
        }

        $model  = ! empty( $settings['anthropic_model'] ) ? trim( $settings['anthropic_model'] ) : 'claude-3-5-sonnet-latest';
        $prompt = self::build_llm_prompt( $text, $target_locale, $settings, 'anthropic' );

        $payload = apply_filters( 'af_translate_llm_request_body', array(
            'model'       => sanitize_text_field( $model ),
            'max_tokens'  => 2000,
            'temperature' => isset( $settings['pro_temperature'] ) ? (float) $settings['pro_temperature'] : 0.1,
            'system'      => $prompt,
            'messages'    => array( array( 'role' => 'user', 'content' => array( array( 'type' => 'text', 'text' => $text ) ) ) ),
        ), 'anthropic' );

        $headers = array( 'x-api-key' => $api_key, 'anthropic-version' => '2023-06-01', 'content-type' => 'application/json' );
        $body    = self::execute_api_post( '[https://api.anthropic.com/v1/messages](https://api.anthropic.com/v1/messages)', $headers, $payload, 25 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['content'][0]['text'] ) ) {
            return self::clean_model_response( $body['content'][0]['text'] );
        }
        return new WP_Error( 'api_error', __( 'Anthropic payload execution failed.', 'af-translate' ) );
    }

    private static function call_grok( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'grok' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Grok API key is empty.', 'af-translate' ) );
        }

        $model  = ! empty( $settings['grok_model'] ) ? trim( $settings['grok_model'] ) : 'grok-4';
        $prompt = self::build_llm_prompt( $text, $target_locale, $settings, 'grok' );

        $payload = apply_filters( 'af_translate_llm_request_body', array(
            'model'       => sanitize_text_field( $model ),
            'temperature' => isset( $settings['pro_temperature'] ) ? (float) $settings['pro_temperature'] : 0.2,
            'messages'    => array(
                array( 'role' => 'system', 'content' => $prompt ),
                array( 'role' => 'user', 'content' => $text ),
            ),
        ), 'grok' );

        $headers = array( 'Authorization' => 'Bearer ' . $api_key, 'Content-Type' => 'application/json' );
        $body    = self::execute_api_post( '[https://api.x.ai/v1/chat/completions](https://api.x.ai/v1/chat/completions)', $headers, $payload, 25 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['choices'][0]['message']['content'] ) ) {
            return self::clean_model_response( $body['choices'][0]['message']['content'] );
        }
        return new WP_Error( 'api_error', __( 'Grok response validation failed.', 'af-translate' ) );
    }

    /**
     * ------------------------------------------------------------------
     * NEURAL MACHINE TRANSLATION (NMT) ENGINES
     * ------------------------------------------------------------------
     */

    private static function call_deepl( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'deepl' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'DeepL API key is empty.', 'af-translate' ) );
        }

        $target_lang = strtolower( substr( $target_locale, 0, 2 ) );
        $endpoint    = ( 'fx' === substr( strtolower( $api_key ), -2 ) ) ? '[https://api-free.deepl.com/v2/translate](https://api-free.deepl.com/v2/translate)' : '[https://api.deepl.com/v2/translate](https://api.deepl.com/v2/translate)';
        
        $payload = apply_filters( 'af_translate_nmt_request_body', array( 'text' => array( $text ), 'target_lang' => strtoupper( $target_lang ) ), 'deepl', $target_lang, $text );
        $headers = array( 'Authorization' => 'DeepL-Auth-Key ' . $api_key, 'Content-Type' => 'application/json' );
        
        $body = self::execute_api_post( $endpoint, $headers, $payload, 15 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['translations'][0]['text'] ) ) {
            return $body['translations'][0]['text'];
        }
        return new WP_Error( 'api_error', __( 'DeepL compilation failed.', 'af-translate' ) );
    }

    private static function call_google( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'google' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Google Translate API key is empty.', 'af-translate' ) );
        }

        $target_lang = strtolower( substr( $target_locale, 0, 2 ) );
        $url         = '[https://translation.googleapis.com/language/translate/v2?key=](https://translation.googleapis.com/language/translate/v2?key=)' . $api_key;
        $payload     = apply_filters( 'af_translate_nmt_request_body', array( 'q' => $text, 'target' => $target_lang, 'format' => 'text' ), 'google', $target_lang, $text );
        
        $body = self::execute_api_post( $url, array(), $payload, 15, false );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['data']['translations'][0]['translatedText'] ) ) {
            return html_entity_decode( $body['data']['translations'][0]['translatedText'], ENT_QUOTES, 'UTF-8' );
        }
        return new WP_Error( 'api_error', __( 'Google Translate request failed.', 'af-translate' ) );
    }

    private static function call_lecto( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'lecto' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Lecto AI API key is empty.', 'af-translate' ) );
        }

        $target_lang = strtolower( substr( $target_locale, 0, 2 ) );
        $payload     = apply_filters( 'af_translate_nmt_request_body', array( 'texts' => array( $text ), 'to' => array( $target_lang ) ), 'lecto', $target_lang, $text );
        $headers     = array( 'X-API-Key' => $api_key, 'Content-Type' => 'application/json' );

        $body = self::execute_api_post( '[https://api.lecto.ai/v1/translate/text](https://api.lecto.ai/v1/translate/text)', $headers, $payload, 15 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body['translations'][0]['to'][0]['translated'][0] ) ) {
            return $body['translations'][0]['to'][0]['translated'][0];
        }
        return new WP_Error( 'api_error', __( 'Lecto AI execution payload failed.', 'af-translate' ) );
    }

    private static function call_microsoft( $text, $target_locale, $settings ) {
        $api_key = self::get_api_key( $settings, 'microsoft' );
        if ( empty( $api_key ) ) {
            return new WP_Error( 'missing_key', __( 'Microsoft Translator API key is empty.', 'af-translate' ) );
        }

        $region      = isset( $settings['microsoft_region'] ) ? trim( $settings['microsoft_region'] ) : 'global';
        $target_lang = strtolower( substr( $target_locale, 0, 2 ) );
        $url         = '[https://api.cognitive.microsofttranslator.com/translate?api-version=3.0&to=](https://api.cognitive.microsofttranslator.com/translate?api-version=3.0&to=)' . $target_lang;
        $payload     = apply_filters( 'af_translate_nmt_request_body', array( array( 'Text' => $text ) ), 'microsoft', $target_lang, $text );
        $headers     = array( 'Ocp-Apim-Subscription-Key' => $api_key, 'Ocp-Apim-Subscription-Region' => $region, 'Content-Type' => 'application/json' );

        $body = self::execute_api_post( $url, $headers, $payload, 15 );
        if ( is_wp_error( $body ) ) {
            return $body;
        }

        if ( isset( $body[0]['translations'][0]['text'] ) ) {
            return $body[0]['translations'][0]['text'];
        }
        return new WP_Error( 'api_error', __( 'Microsoft Translator verification failed.', 'af-translate' ) );
    }

    /**
     * ------------------------------------------------------------------
     * RESOLVERS & SANDBOX SYSTEM
     * ------------------------------------------------------------------
     */

    private static function resolve_active_provider( $settings, $explicit_provider = '' ) {
        if ( ! empty( $explicit_provider ) ) {
            return sanitize_key( $explicit_provider );
        }

        if ( ! empty( $settings['active_provider'] ) ) {
            $active = sanitize_key( $settings['active_provider'] );
            if ( ! empty( $settings[ $active . '_key' ] ) && 'sandbox-test-key' !== $settings[ $active . '_key' ] ) {
                return $active;
            }
        }

        foreach ( array( 'gemini', 'openai', 'anthropic', 'grok', 'deepl', 'microsoft', 'google', 'lecto' ) as $provider ) {
            if ( ! empty( $settings[ $provider . '_key' ] ) && 'sandbox-test-key' !== $settings[ $provider . '_key' ] ) {
                return $provider;
            }
        }
        return 'gemini';
    }

    private static function is_sandbox_mode( $settings, $provider ) {
        if ( 'openai' === $provider && 'sandbox-test-key' === get_option( 'af_translate_api_key', '' ) ) {
            return true;
        }
        $api_key = isset( $settings[ $provider . '_key' ] ) ? trim( $settings[ $provider . '_key' ] ) : '';
        return ( empty( $api_key ) || 'sandbox-test-key' === $api_key );
    }

    private static function simulate_single_sandbox( $text, $locale ) {
        usleep( 600000 );
        return "[Sandbox - Language Target: " . strtoupper( esc_html( $locale ) ) . "]: " . $text;
    }

    private static function simulate_batch_sandbox( $strings_array, $locale ) {
        usleep( 1200000 );
        $mocked_catalog = array();
        foreach ( $strings_array as $index => $text ) {
            $mocked_catalog[ $index ] = "[Bulk Sandbox - " . strtoupper( esc_html( $locale ) ) . "]: " . $text;
        }
        return $mocked_catalog;
    }
}